Method for operating a data processing unit of a driver assistance system and data processing unit

ABSTRACT

A method for operating a data processing unit of a driver assistance system, the unit including main and slave computers. The main computer ascertains surroundings data from a surroundings detection system by using a processing specification. The slave computer operates a communication interface of the data processing unit, using a communication instruction. The method includes initializing, a first testing, a carrying out, a second testing and a forwarding. In initializing, the main computer, in response to a signal, is initialized by performing an initialization instruction on the main computer. In the first testing, the slave computer, in response to the signal, is initialized by performing a self-test instruction on the slave computer. In the carrying out, the communication instruction is performed on the slave computer to send and/or receive data via the communication interface, when the slave computer is tested and while the main computer is initialized. In the second testing, the main computer is tested by performing a test instruction on the slave computer, when the main computer is initialized. In the forwarding, the surroundings data are forwarded via the communication interface by performing the communication instruction on the slave computer, when the main computer is tested.

RELATED APPLICATION INFORMATION

The present application claims priority to and the benefit of Germanpatent application no. 10 2015 202 326.5, which was filed in Germany onFeb. 10, 2015, the disclosure of which is incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to a method for operating a dataprocessing unit of a driver assistance system, to a data processing unitand to a corresponding computer program.

BACKGROUND INFORMATION

A safety-relevant system of a vehicle requires a functional test toensure normal operation.

SUMMARY OF THE INVENTION

Against this background, the approach presented here introduces a methodfor operating a data processing unit of a driver assistance system, adata processing unit and ultimately a corresponding computer program asdescribed herein. Further advantageous embodiments result from theparticular further descriptions herein and the subsequent description.

The functional test of a complex data processing unit may requireconsiderable time. In this context, the functional test may take longerthan is required for activating a data bus to which the data processingunit is connected. The reason is that data are already transported onthe data bus; however the data processing unit is not able yet toprovide a status message regarding the data bus, since the functionaltest is not yet completed.

With the approach presented here, a less powerful slave computer ispositioned between a powerful main computer of the data processing unitand the data bus for the communication via the data bus. The slavecomputer is less complex than the main computer, which is why the slavecomputer may be booted faster than the main computer. As a result, thedata processing unit may be rapidly integrated into the data bus.Nevertheless, computer programs may be executed both on the slavecomputer as well as on the main computer.

Due to the shorter boot time, the slave computer may already communicatevia the data bus while the main computer still boots up. The data busmay therefore establish its normal connections, while the main computerconcurrently still passes through its initialization sequence.

When the main computer is booted up, the slave computer may check tomonitor the main computer and provide the data from the main computervia the data bus.

A method for operating a data processing unit of a driver assistancesystem is presented, the data processing unit including a main computerand a slave computer, the main computer being configured forascertaining surroundings data from surroundings information of asurroundings detection system by using a processing specification andthe slave computer being configured for operating a communicationinterface of the data processing unit by using a communicationinstruction, the method including the following steps:

initializing the main computer by carrying out an initializationinstruction on the main computer in response to an initializationsignal;

testing the slave computer by carrying out a self-test instruction onthe slave computer, in response to the initialization signal;

carrying out the communication instruction on the slave computer to sendand/or receive data via the communication interface when the slavecomputer is tested and while the main computer is being initialized;

testing the main computer by carrying out a test instruction on theslave computer when the main computer is initialized; and

forwarding the surroundings data via the communication interface bycarrying out the communication instruction on the slave computer, whenthe main computer is tested.

Furthermore, a data processing unit of a driver assistance system ispresented, the data processing unit including the following features:

a main computer which is configured for ascertaining surroundings datafrom surroundings information of a surroundings detection system byusing a processing specification; and

a slave computer which is configured for operating a communicationinterface of the data processing unit by using a communicationinstruction.

A data processing unit may be understood to be a subcomponent of adriver assistance system for a vehicle. The driver assistance system mayinclude at least one sensor for gathering a piece of surroundingsinformation from surroundings of the vehicle, the data processing unitfor evaluating the piece of surroundings information and at least oneexecution unit for carrying out an action in response to a result of theevaluation. The subcomponents of the driver assistance system areinterlinked or connected to one another. As a result, information may beexchanged between the subcomponents. A computer may be designated as aprocessor core, a processor or a microcontroller. Software may beexecuted on the computer. The main computer may have more computingcapacity than the slave computer. The slave computer may be less complexor be structured (i.e. circuitry-wise or numerically) less complicatedthan the main computer. The data processing unit is connected to theexecution unit via a data bus. The data bus connects a multitude ofusers to each other and includes a communication protocol.

Initialization may be understood as starting-up or as booting-up. Forthis purpose, an initialization sequence is run through, which checksindividual components of the main computer and synchronizes them withone another. The initialization sequence takes a certain time. Theinitialization sequence is mapped by a software-based initializationinstruction.

The testing of the slave computer may take less time than theinitialization of the main computer. Thereafter, the slave computer mayalready take control over the communication of the data processing unit.

The method may include a step of waiting, in which the slave computerwaits after the step of carrying out until the main computer isinitialized. The slave computer may wait for a predetermined timeperiod. If the main computer is not initialized after the time periodhas elapsed, an error may be detected.

During the step of waiting, the slave computer may interrupt the sendingand/or receiving of data via the communication interface. As a result ofthe wait, the data volume on the data bus may be reduced.

During the step of carrying out and/or during the step of forwarding, asecure communication protocol may be used by the slave computer. In thatcontext, preassembled data packets may be transmitted. The securecommunication protocol may represent, for example, that no inquiriesdirected to the data processing unit will be processed. In the presentcase, a secure communication protocol may be understood as being acommunication protocol, in which the data transfer is protected againsterrors using error detection or error correction methods.

The step of testing the main computer may be repeated periodically.

For this purpose, the step of forwarding may be carried out in parallelby the slave computer. The functional efficiency of the main computermay virtually be checked continuously by periodic testing.

The initialization signal may be provided during the step of testing themain computer, if an error is detected. The main computer may be checkedagain easily and quickly by repeating the starting sequence.

A computer program product or computer program having program code,which may be stored on a machine-readable carrier or storage medium suchas a semiconductor memory, a hard-disk storage unit or an optical memoryis also advantageous, and which is used for carrying out, implementingand/or activating the steps of the method according to one of thespecific embodiments described above, in particular if the programproduct or program is executed on a computer or a device.

Electronic systems are used in many safety-relevant applications. Forthis purpose, typically computers or microcontrollers (pC) andapplication-specific integrated circuits (ASICs) may be used in anautomobile, to appropriately represent both the functionality as well asthe safety. For this purpose, the ASIC takes over the monitoring, i.e.to monitor the microcontroller, and frequently also to trigger theshutdown path.

To secure the microcontroller, a second microcontroller may also beused. This recalculates the components or even the entire implementedmethod. By using suitable comparators, it is ensured that the output isprovided only if there is equality between the two microcontrollers interms of the monitored variables. The redundancy used in avionics iseven higher.

When used in the area of driver assistance systems, which process verycomprehensive surroundings data, the direct application of theseprinciples is difficult, since the microcontrollers involved are verypowerful and correspondingly expensive. Duplication within these budgetconstraints is therefore not always feasible. The boot or initializationprocess including all necessary monitoring tests of such amicrocontroller takes a long time, and therefore in some cases it may benecessary to represent sub-functions already before the microcontrollerhas been fully tested. This process takes too long also in cases oftransient errors and interferences.

The approach presented here is explained in greater detail below, withreference to the attached drawings.

In the following description of favorable exemplary embodiments of thepresent invention, identical or similar reference numerals are used forthe elements illustrated in the different figures which functionsimilarly, a repeated description of these elements being dispensedwith.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of a component of a driver assistancesystem according to one exemplary embodiment of the present invention.

FIG. 2 shows a block diagram of a main controller according to oneexemplary embodiment of the present invention.

FIG. 3 shows a block diagram of a main controller including twoprocessor cores according to one exemplary embodiment of the presentinvention.

FIG. 4 shows a flow chart of a method for operating a component of adriver assistance system according to one exemplary embodiment of thepresent invention.

FIG. 5 shows a flow chart of a restart of a component of a driverassistance system according to one exemplary embodiment of the presentinvention.

DETAILED DESCRIPTION

FIG. 1 shows a block diagram of a data processing unit 100 of a driverassistance system according to one exemplary embodiment of the presentinvention. Data processing unit 100 includes a main computer 102 and aslave computer 104. Both computers 102, 104 are configured to executeprograms which are drawn up in machine language. In this context,different programs may be executed and computers 102, 104 may be usedfor different tasks. In one exemplary embodiment, main computer 102 hasa significantly greater computing capacity than slave computer 104.

Main computer 102 is connected via an interface to a surroundingsdetection system 106 and may receive surroundings information 108 fromsurroundings detection system 106 via the interface. Main computer 102is configured for ascertaining surroundings data 112 from surroundingsinformation 108, by using a processing specification 110 contained in aprogram. Slave computer 104 is connected to main computer 102 via aninternal interface. Slave computer 104 is situated between main computer102 and a communication interface 114 of data processing unit 100 to adata bus. Slave computer 104 is configured for operating communicationinterface 114 by using a communication instruction 116 mapped in aprogram. For this purpose, surroundings information 112 is synchronizedwith other information on the data bus and is provided via communicationinterface 114 during normal operation.

The data bus may be a CAN bus. A communication protocol of the data busis mapped in communication instruction 116.

A fail-safe microcontroller 104 for driver assistance systems ispresented.

In this context, a system or control unit architecture 100 is presented,which permits appropriate monitoring, so that the relevant boot timewhich is visible in the integrated network is small and an errortolerance against transient interferences is implemented.

For the representation of a driver assistance system (DAS), in which theactuating elements for the considered control unit function arerepresented via the communication system, it is provided that inaddition to the main computer of driver assistance system (DAS pC) 102,which evaluates surroundings sensor system (SSS) 106, an additionalintrinsically safe microcontroller (SpC) 104 is used. This fail-safemicrocontroller 104 is used to represent communication interface 114 ofcontrol unit 100 in particular with regard to the considered function tothe outside. For this purpose, CAN interface 114 is served by fail-safemicrocontroller 104. However, another communication protocol is alsopossible. Fail-safe microcontroller 104 is further capable to operatecommunication interface 114 in the fail-safe state of the driverassistance system in such a way that a functional control unit 100 withregard to communication is represented externally. With driverassistance system microcontroller 102, fail-safe microcontroller 104 iscapable of implementing both a functional communication, during whichthe message contents are transmitted from driver assistance systemsmicrocontroller 102 to fail-safe microcontroller 104, as well as amonitoring communication, during which fail-safe microcontroller 104implements monitoring of driver assistance system microcontroller 102.

An important advantage results from the fact that the boot time ofsystem 100, which is visible to the outside (i.e. on the communicationside) is short and independent of the boot, initialization or test timeof driver assistance system microcontroller 102, since the buscommunication is served entirely by fail-safe microcontroller 104.Moreover, the reset and error handling mechanisms of the main system,which are represented on driver assistance system microcontroller 102,may be encapsulated while maintaining the secure communication ofcontrol unit 100. An independent shutdown path of system 100 may beimplemented with the aid of fail-safe microcontroller 104. Fail-safemicrocontroller 104 may implement a monitoring functionality for driverassistance system microcontroller 102, for example via a secure andindependent comparator or via a question and answer communication.

A potential representation of system 100 is described in FIG. 1.Surroundings sensor system SSS 106 provides surroundings data 108, forexample via stereo/mono video, Lidar, radar or ultrasonic sensor system106. Data 108 measured by this sensor system 106 are optionally sent viasuitable intermediate and pre-processing stages which are not shown,such as Imagers, for example, to driver assistance systemmicrocontroller 102, in which different algorithms 110 are running forevaluation and interpretation of surroundings sensor system data 108.These may be algorithms 110 for image processing, for example, forobject modeling or for situation analysis.

In other words, a control unit 100 for a driver assistance systemincluding at least two chips 102, 104 is presented. One of the chips 102monitors a surroundings sensor system 106 and the other 104 monitorscommunication 110. A secure state of system 100 may be represented, ifcommunication chip 104 does not send specific messages.

Furthermore, a question and answer query may occur between the two chips102, 104. During the start-up of system 100, the communication chip 104is first activated and transmits noncritical messages.

If an error or interference occurs in function computer 102, functioncomputer 102 may be re-booted, while the other function computer servescommunication interface 110.

FIG. 2 shows a block diagram of a main computer 102 according to oneexemplary embodiment of the present invention. Main computer 102corresponds essentially to the main computer in FIG. 1. Here, elementsof main computer 102 are represented additionally. In this context, maincomputer 102 includes at least one processor core 200, one cache 202,one FPGA 204, memory modules 206 and periphery 208. Main computer 102may moreover include further constituents 210. Via additionalinterfaces, main computer 102 may access external memory modules 212,such as RAM and/or Flash.

As FIG. 2 illustrates, the driver assistance system microcontroller 102may contain different elements. Driver assistance system microcontroller102 may in particular include FPGAs 204, cores 200, caches 202 indifferent stages and characteristics, internal memories 206, periphery208 and many other possible constituents 210. The driver assistancesystems microcontroller may still use external memory modules 212 likeRAMs or Flashes as well.

It is typical for such a complex driver assistance systemmicrocontroller 102 that the initialization time including the testtakes relatively long and is associated with great complexity. Suchtests are necessary, however, if a safety-relevant function isrepresented on the system.

If driver assistance system microcontroller 102 were to control thecommunication directly, i.e., if it were linked directly to thecommunication component, then it would be difficult to send messageswithin a very short time via the data bus, the correctness of whichcould be guaranteed. During the use in a motor vehicle, it is frequentlyimportant, however, that a control unit is already visible on thecommunication system within a very short time.

But then it would be possible that only a few of the components weretested, for example only internal RAM 206, before the first CAN messageis sent. To circumvent this, the approach presented here suggests toinsert a fail-safe microcontroller between driver assistance systemmicrocontroller 102 and the data bus, in particular the CAN bus, whichcontrols the communication.

FIG. 3 shows a block diagram of a main computer 102 including twoprocessor cores 200, 300 according to one exemplary embodiment of thepresent invention. In this context, main computer 102 essentiallycorresponds to the main computer in FIG. 2. Main computer 102 inaddition has a second processor core 300. Processing specification 110may be carried out on both processor cores 200, 300, at least partially.As a result, both processor cores provide surroundings data 112.Surroundings data 112 of both processor cores 200, 300 are compared withone another, at least partially, in slave computer 104, in order tomonitor the function of main computer 102. Surroundings data 112 areprovided by slave computer 104 via the communication interface and thedata bus only if main computer 102 operates normally.

Driver assistance system microcontroller 102 may include multiplesubcomponents C1, C2, 200, 300. These are cores 200, 300 or FPGAs, forexample, which both provide results 112 which are comparable. Aninternal comparison is potentially possible. An external comparison onthe other hand has advantages regarding the susceptibility to commoncause failure. If C1 and C2 send their results 112 to fail-safemicrocontroller 104, the external comparison may be carried out there.This external comparison may also be more complex than simply abit-by-bit comparator, since fail-safe microcontroller 104 hascorresponding computing capacities. For example, a chronologicallyslower signal 112 of the one subcomponent 200 of the driver assistancesystem microcontroller may be compared with a chronologically fastersignal 112 of another subcomponent 300 of driver assistance systemmicrocontroller 102. It is also possible to carry out a plausibilitycheck between two different variables.

FIG. 4 shows a flow chart of a method 400 for operating a dataprocessing unit of a driver assistance system according to one exemplaryembodiment of the present invention. A data processing unit of a driverassistance system, as shown in FIG. 1 for example, may be operated bymethod 400. Method 400 includes a step 402 of initializing, a step 404of testing, a step 406 of carrying out, a further step 408 of testingand a step 410 of forwarding. In this context, steps 402, 408, 410 whichrefer to main computer 102 in terms of time correlation are applied viasteps 404, 406, 408, 410 of slave computer 104.

In step 402 of initializing, main computer 102 is initialized bycarrying out an initialization instruction on main computer 102 inresponse to an initialization signal. In step 404 of testing, slavecomputer 104 is tested by carrying out a self-test instruction on slavecomputer 104 in response to the initialization signal. In step 406 ofcarrying out, the communication instruction is carried out on slavecomputer 104, in order to send and/or receive data via the communicationinterface, when slave computer 104 is tested and while main computer 102is being initialized. In step 408 of testing, main computer 102 istested by carrying out a test instruction on slave computer 104, whenmain computer 102 is initialized. In step 410 of forwarding, thesurroundings data are forwarded via the communication interface bycarrying out the communication instruction on slave computer 104, whenthe main computer 102 is tested.

After the start of the system, both driver assistance systemsmicrocontroller 102 as well as fail-safe microcontroller 104 begin withthe initialization 404, 402. After this phase 404 including allself-tests in fail-safe microcontroller 104 has taken place, fail-safemicrocontroller 104 begins to represent communication 406 in the secureform on the CAN bus, for example. After communication 406 runs,fail-safe microcontroller 104 waits 412. Secure communication 406 isretained during waiting 412. Externally, a secure, in particular passivesystem is therefore visible at all times. The waiting time may belimited by a timer. If there are no errors, the waiting time ends whenfail-safe microcontroller 104 receives information from driverassistance system microcontroller 102 stating that it has finished.During the entire time, initialization 402 runs in driver assistancesystem microcontroller 102, which could and should include comprehensiveself-tests and checks. These self-tests may include memory checks,calculation tests, peripheral tests or further initialization tests.During this time, calibration tasks may also be carried out, which maybe set up at the beginning of the system start. After thisinitialization 402 has been completed, driver assistance systemmicrocontroller 102 sends the message or information to fail-safemicrocontroller 104. For this purpose, any interface may be used, e.g.SPI, which may then also be secured with the aid of different methods,such as Parity, ECC, ECR. Advantageously, the message is generated insuch a way that it may be transmitted correctly only after thecompletion of a correct initialization process 402. Fail-safemicrocontroller 104 receives the message. If the message was correctlysent in the correct time window, an external test phase 408 begins.During this test phase, a test pattern is sent as an inquiry fromfail-safe microcontroller 104 to driver assistance systemmicrocontroller 102, the response to which is the task of driverassistance system microcontroller 102. If the inquiry was correctlyanswered in the correct time window, fail-safe microcontroller 104assumes that driver assistance system microcontroller 102 is correct.Different variants may be used for this question and answercommunication, for example by preparing the question, debouncing, byincluding a program sequence test and/or an error counter. This phase408 serves actually also for reciprocal monitoring. Thereafter, or inparallel, since external test 408 may run during the entire normaloperation 410, normal operation 410 begins. In this phase 410, fail-safemicrocontroller 104 takes over the communication to the outside, thecontent of the messages is provided by driver assistance systemmicrocontroller 102, but for this purpose fail-safe microcontroller 104is able to evaluate the correct functionality of driver assistancesystem microcontroller 102 by using the messages.

The application of the approach presented here is in particularmeaningful, if the scope of functions to be implemented of theconsidered driver assistance system meets two conditions. Initially, afail-safe characteristic should exist. This means that there is a securestate of the system where no risk originates from the system. The secondcondition is that the functional system states may be differentiatedinto two categories, an active one and a passive one. In this context,the passive one represents the normal case where most of the drivingtime is spent. The passive one corresponds to the secure state in thiscase. This is the case for an emergency braking system, for example.This normally does not intervene, it is therefore passive, and the“non-intervention” is the secure state. This characteristic applies topractically all assistance systems which intervene only in exceptionalcases.

In the normal case, fail-safe microcontroller 104 always sends messagesvia the communication which signal the secure state, i.e., a passivesystem, for example. This may still be a somewhat more complex messagepattern, since a changing format may also be used for “constant”messages, for example a message counter, to be able to detect errors atsystem level. However, this task may also be administered even by a verysimply configured fail-safe microcontroller 104, which is at a levelseveral performance categories below that of driver assistance systemmicrocontroller 102.

FIG. 4 in principle outlines a potential sequence of initializing asystem according to the approach presented here. In the image, the stepsare plotted across time t.

In this context, a so-called question and answer method may be used formonitoring. For this purpose, a question may be asked of microcontroller102, for the response to which microcontroller 102 requires a certainportion of its functionality. The correct response within a predefinedtime period is interpreted as an indication of microcontroller 102 beingoperating correctly.

In one exemplary embodiment, method 400 includes a step 412 of waitingwhich follows step 406 of carrying out, in which no further data aretransmitted via the communication interface until step 402 ofinitializing is completed. In this context, the communication is startedvia the data bus in step 406 of carrying out as secure communication, inorder to accomplish a reduced time delay during activation of the databus. In step 412 of waiting, there is no need for sending data packetsvia the data bus, since the main computer is not yet ready to providesurroundings data.

FIG. 5 shows a flow chart of a restart of a component of a driverassistance system according to one exemplary embodiment of the presentinvention. In this context, essentially the same steps are carried outas in FIG. 4. Here, the restart is triggered by a detection 500 of anerror. Detection 500 results from step 408 of testing, which is carriedout periodically or continuously in parallel to step 410 of forwarding,to check the main computer.

Subsequently to detection 500, step 402 of initializing is carried outon the main computer, while the slave computer carries out thecommunication instruction without a further self-test in step 406, inorder to maintain the communication via the data bus. When step 402 ofthe initializing is carried out, step 408 of testing is carried out asin FIG. 4, and when the main computer is deemed to be functional, step410 of forwarding is carried out as in FIG. 4.

There are different ways of detecting an error in driving assistancesystem microcontroller 102. Initially, the internal measures in driverassistance system microcontroller 102 are a potential source. Thedetection may also be carried out by fail-safe microcontroller 104. Inprinciple, the approach presented here permits an encapsulated sequenceof error handling, as it is illustrated in FIG. 5.

Error detection 500 takes place in one of microcontrollers 102, 104involved. In any case, fail-safe microcontroller 104 is notified that anerror exists. This came about by the absence of messages and monitoringresponses, for minor errors this may also come about by an explicitcommunication from driver assistance system microcontroller 102 tofail-safe microcontroller 104. Thereafter, fail-safe microcontroller 104projects a secure state to the outside regarding secure communication406, in particular a safe CAN. Meanwhile, test and recovery procedure402 proceeds on driver assistance system microcontroller 102. Whichtests are running depends on the detected error or on the respondingerror detection mechanism. For a memory error in RAM, which was detectedvia a parity, for example, a memory test is sufficient. For an error,which was detected by external monitoring, i.e. by the fail-safemicrocontroller, it may be necessary to test the entire driverassistance system microcontroller 102, including any external elementswhich may be present. The recovery procedures and times of recoverydiffer accordingly.

Fail-safe microcontroller 104 recognizes a maximum period for which therespective relevant structure must be maintained, and signals to theoutside that the system is no longer functional, if driver assistancesystem microcontroller 102 does not comply with this time. Otherwise,external test phase 408 is started the same way as with theinitialization 402, and normal operation 410 resumes. Due to thismethod, all transient or tolerable errors may be encapsulated to theoutside while maintaining the secure state.

One variant of this method may be implemented in that defective device(DAS pC) 102 is completely reset after error detection 500 and test andinitialization phase 402 is represented by startup phase 402 of thesystem. This has the advantage that only one start phase 402 isrequired, which may take somewhat longer than an error specific recoveryprocess. It is then also particularly meaningful to count the number ofreset processes in fail-safe microcontroller 104, or to measure thechronological frequency of the resets. By limiting the counter or themeasuring result, for example relative to an ignition cycle or theservice life, it is possible to prevent accumulation of errors and causethe system to be switched off, if a critical permanent error exists.

The approach presented here may also provide monitoring support. In thiscontext, fail-safe microcontroller 104 also still yields an advantagefor security or monitoring. As an independent module, fail-safemicrocontroller 104 may test driver assistance system microcontroller102 via the question and answer communication. Fail-safe microcontroller104 may represent the shutdown path also in an independent form. Andfinally, fail-safe microcontroller 104 may permit an independentcomparison function.

The exemplary embodiments described and illustrated in the figures areselected merely as examples. Different exemplary embodiments may becombined completely or by reference to individual features with oneanother. One exemplary embodiment may also be supplemented by featuresof a further exemplary embodiment.

Moreover, the method steps presented here may be repeated also in asequence other than the one described.

If an exemplary embodiment includes an “and/or” linkage between a firstfeature and a second feature, then this is to be read in such a way thatthe exemplary embodiment according to one specific embodiment includesboth the first feature as well as the second feature and according to afurther specific embodiment includes either only the first feature oronly the second feature.

What is claimed is:
 1. A method for operating a data processing unit ofa driver assistance system, the data processing unit including a maincomputer and a slave computer, the method comprising: initializing themain computer by carrying out an initialization instruction on the maincomputer; testing the slave computer by carrying out a self-testinstruction on the slave computer; carrying out the communicationinstruction on the slave computer, to transmit and/or receive data via acommunication interface while the main computer is being initialized;testing the main computer by carrying out a test instruction on theslave computer; and forwarding the data via the communication interfaceby carrying out the communication instruction on the slave computer;wherein the main computer is for ascertaining data from surroundingsinformation from a surroundings detection system by using a processingspecification and the slave computer is for operating the communicationinterface of the data processing unit by using a communicationinstruction.
 2. The method of claim 1, further comprising: waiting, inwhich the slave computer subsequent to the carrying out waits until themain computer is initialized.
 3. The method of claim 2, wherein theslave computer during the waiting interrupts the transmission and/orreception of data via the communication interface.
 4. The method ofclaim 1, wherein a secured communication protocol is used by the slavecomputer during the carrying out.
 5. The method of claim 1, wherein asecured communication protocol is used by the slave computer during theforwarding.
 6. The method of claim 1, wherein the testing of the maincomputer is repeated periodically, the forwarding being carried out inparallel by the slave computer.
 7. The method of claim 1, wherein duringthe testing of the main computer the initialization signal is provided,if an error is detected.
 8. A data processing unit of a driverassistance system, comprising: a main computer to ascertain surroundingsdata from surroundings information of a surroundings detection system byusing a processing specification; and a slave computer to operate acommunication interface of the data processing unit by using acommunication instruction.
 9. A computer readable medium having acomputer program, which is executable by a processor, comprising: aprogram code arrangement having program code for operating a dataprocessing unit of a driver assistance system, the data processing unitincluding a main computer and a slave computer, by performing thefollowing: initializing the main computer by carrying out aninitialization instruction on the main computer; testing the slavecomputer by carrying out a self-test instruction on the slave computer;carrying out the communication instruction on the slave computer, totransmit and/or receive data via a communication interface while themain computer is being initialized; testing the main computer bycarrying out a test instruction on the slave computer; and forwardingthe data via the communication interface by carrying out thecommunication instruction on the slave computer; wherein the maincomputer is for ascertaining data from surroundings information from asurroundings detection system by using a processing specification andthe slave computer is for operating the communication interface of thedata processing unit by using a communication instruction.
 10. Thecomputer readable medium of claim 9, further comprising: waiting, inwhich the slave computer subsequent to the carrying out waits until themain computer is initialized.